JPH07245831A - Gas-insulated switchgear - Google Patents

Abstract

PURPOSE:To get information for the early recovery at the time of an accident by accurately judging an accident block, using the magnitude of a current for detection of the accident. CONSTITUTION:A gas-insulated switchgear 3, where a container for accommodating each element is divided into a plurality of gas blocks, are provided with current detectors, which severally detect the currents of three-phase buses built in insulating spacers 1AB, 1AC, 1CD, 1DE, 1DF, 1E, 1F, and 1A for dividing each gas block, and an accident block judging part 4, which compares the magnitude of this current with the specified judgment level and judges the gas block of accident occurrence.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas insulated switchgear (hereinafter referred to as GIS).

[Prior art]

In general, GIS is one of the substation equipments.
Devices other than transformers, such as circuit breakers, disconnectors, grounding switches, and transformers, are housed in metal containers filled with an insulating gas such as SF6 gas, and the units are divided into gas compartments by insulating spacers. As a result, GIS realizes downsizing of the device by gas insulation, improvement of reliability, operation and maintenance, and safety without exposing the charging part. But on the other hand,
In GIS, since each device is sealed in a metal container,
If an internal accident should occur, it may be difficult to find the gas compartment where the accident occurred, and it may take time to recover.

Examples of internal accidents are caused by a pointed accident (ground fault or interphase short circuit) due to insulation deterioration due to partial discharge due to conductive foreign substances mixed in the container, and a poor contact at a busbar connection portion inside the container. There are cases where the conductor melts to a pointed tip.

Conventionally, when an internal accident occurs, the pressure in the metal container rises, so it has been tried to monitor the gas pressure and accurately determine the accident zone.

FIG. 3 shows an example of the structure of GIS. GIS3
The gas compartments A to F are separated by an insulating spacer 1. The gas section A has a cable connection (CH), the gas section B has an instrument transformer (PT), the gas section C has a disconnector (DS) and a grounding switch (ES), and the gas section D has a The instrument current transformer (CT) and the circuit breaker (CB) are housed in the gas section E and the gas section F, respectively. Another of gas compartment E and gas compartment F
A bus bar (BUS) connected to another line is connected to the end.

FIG. 4 shows an example of a case where a conventional gas pressure is monitored to detect an accident section. The GIS 3 is divided into gas sections A to F by an insulating spacer 1 '. A valve 61 and a pressure sensor 62 are attached to each gas compartment via a pipe 60. The pressure signal of each gas section detected by each pressure sensor 62 is sent to each electric cable 63.
Then, it is sent to the signal processing circuit 7. In the signal processing circuit 7,
In order to amplify the signal in each amplifier 71 and to remove the influence of the reflection collision of gas, each low pass filter 7
The high frequency component is removed at 2, and the pressure time change detection circuit 73
Send to. The pressure time change detection circuit 73 detects the time change Δp of the pressure for each gas section, and detects the pressure time change Δp.
p and the gas section information N are sent to the accident section determination circuit 74. The time change Δp is compared with the judgment level preset by the judgment level setting circuit 75 and the accident section judgment circuit 74, and the gas section exceeding the judgment level is output as the accident section N ′.

[0007]

However, the method of determining the gas compartment where the accident has occurred by monitoring the gas pressure has the following problems.

In order to attach a pressure sensor via a pipe, there is a difference between the pressure detected by the pressure sensor and the actual pressure in the gas compartment, and when detecting a pressure that changes rapidly with time, such as impact pressure at the time of an accident. In particular, the accuracy of pressure change detection may deteriorate depending on the shape of the pipe and the structure of the internal equipment.

It is necessary to set the judgment level depending on the size of the gas compartment and the structure of the storage device. If the setting is incorrect, an accident in which the change in pressure with time is slow cannot be detected, or conversely, it is not an accident. Occasionally, the change in pressure over time may be determined to be an accident. In order to avoid this, it is necessary to repeat the experiment for each gas section to set an accurate determination level, and setting the determination level is complicated.

Further, since the pressure changes depending on the temperature, when there is a difference in the gas temperature rise due to the gas compartment due to the difference in the external environmental conditions such as solar radiation and wind speed and the magnitude of the current flowing in the gas compartment, there is a change in the gas pressure with time. A difference occurs, and the pressure-time change in the gas compartment with a large temperature rise becomes large, but in order not to judge that gas compartment as an accident, the judgment level must be set high, and the resolution of the judgment is limited.

Therefore, the present invention is intended to accurately determine the accident section without being affected by the size of the gas section, the storage equipment, and the temperature.

[0012]

According to a first aspect of the present invention, in a GIS in which a container accommodating each element is divided into a plurality of gas compartments, a three-phase bus bar built in an insulating spacer for partitioning each gas compartment is provided. A current detection unit that is a detection target and an accident section determination unit that determines the gas section in which an accident has occurred by comparing the magnitude of the time change of the current flowing through each insulating spacer with a predetermined determination level are provided.

According to the second aspect of the invention, the current flowing through the other insulating spacer is used as the predetermined determination level of the accident section determination section.

According to the third aspect of the present invention, in the accident section determination unit, the vector sum of the three-phase currents in each insulating spacer is obtained, the zero-phase current is calculated, and the magnitude of the zero-phase current or the time of the zero-phase current is calculated. The magnitude of change is compared to a predetermined decision level to determine the gas compartment in which the accident occurred.

According to another aspect of the present invention, the current detector is composed of a photocurrent detector.

[0016]

In the invention of claim 1, the occurrence of an accident can be determined by detecting the magnitude of the current. Further, since the current increases only on the power supply side of the gas section where the accident has occurred, the section where the current has increased and the section where the current has not increased are discriminated, and the boundary can be known to easily discriminate the fault section. Furthermore, the cause of the accident can be estimated by comparing the current increase for each phase.

According to the second aspect of the present invention, since the current flowing through the other insulating spacer is used as the predetermined determination level of the accident section determination section, there is a slight increase in the current that cannot be detected when the predetermined determination level is used. Since an accident can also be detected, the accident area can be determined more accurately.

According to the third aspect of the present invention, since the accident is detected by utilizing the zero-phase current or its time change, the current change at the time of the accident is smaller than that when the current flowing through the insulating spacer is detected. Since it is large, it is possible to accurately determine the accident zone.

In the invention of claim 4, since the photocurrent detector is used as the current detecting means, the insulation between the main circuit and the current detector is facilitated, and the influence of noise generated when a large current flows at the time of an accident is reduced. Since it is not received, it is possible to more accurately determine the accident section.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the GIS of the first aspect of the invention. The cable section (C
H), the instrument transformer (PT) in the gas compartment B, the disconnector (DS) and the earthing switch (ES) in the gas compartment C.
However, an instrument current transformer (CT) and a circuit breaker (CB) are stored in the gas section D, and a disconnector (DS) is stored in the gas section E and the gas section F, respectively. At the other end of the gas section E and the gas section F, a bus bar (B
US) is connected.

Gas compartments A to F are divided into gas compartments by insulating spacers 1AB, 1AC, 1CD, 1DE, 1DF, 1E, 1F, 1A, respectively. Each insulating spacer 1AB,
Each of 1AC, 1CD, 1DE, 1DF, 1E, 1F, and 1A has a built-in current detection unit for each phase, and its output is transmitted to the accident section determination unit 4 via the current signal transmission unit 2. In the accident section judging unit 4, the judgment level is compared with the magnitude of the current, and if it is larger than the judgment level, it is judged as a section in which the accident current is flowing. Comparing the outputs of all detectors to assess the accident zone,
Output the accident section.

Consider a case where an interphase short circuit accident occurs between the S phase and the T phase in the gas compartment C. Generally, the electric current flows in the gas section as A, C, D, and flows through E or F to another line. When an accident occurs in the gas compartment C, the outputs of the S-phase and T-phase current detectors built in the insulating spacer 1AC increase due to the accident, so the judgment level is exceeded and the accident can be detected. On the other hand, since the S-phase and T-phase currents of the insulating spacer 1CD do not increase, it can be seen that an accident occurred between the insulating spacer 1CD and 1AC. Furthermore, if attention is paid to the fact that the current of the R phase does not increase, it can be seen that there is a short circuit accident between the S phase and the T phase.

If the currents of 1A, 1AC, 1CD, 1DE and 1E or 1DF and 1F all increase, this G
Judged as an accident outside the IS.

According to the second aspect of the present invention, the output of another current detecting section is used as the determination level of the accident section determining section 4. For example, it is possible to use the output of the current detection unit on the load side of the insulating spacer that incorporates the current detection unit. In this case, the current flowing through the spacer on the power supply side of the section where the accident has occurred increases due to the accident, but the current flowing through the spacer on the load side is determined by the size of the load and does not change. Therefore, if the output of the current detection unit of the spacer on the load side is used as the determination level of the accident section determination unit 4, the output of the current detection unit of the spacer on the power supply side, that is, the increase in the current flowing through the spacer is fixedly determined. It can be detected more accurately than the level.

In the third aspect of the invention, in the accident section judging section 4, the outputs of the R phase, the S phase and the T phase are combined in a vector manner to obtain a zero phase current. Although the phase current is zero or close to zero, it can be detected by comparing the magnitude of the zero-phase current or its change over time with the determination level by utilizing the fact that it greatly fluctuates at the time of an accident.

According to the invention of claim 4, a photocurrent detector is used as the current detector. However, since the range of current to be detected is wide, an iron core with magnetic saturation is not used,
A circuit-type photocurrent detector using the Faraday effect is desirable. An example in which a photocurrent detector built in an insulating spacer is used will be described with reference to FIG. The insulating spacer is composed of a metal flange 13 and a spacer portion 15 made of epoxy resin 14, and three-phase conductors 12a, 12b and 12c penetrating the spacer portion 15. Conductor 12
The photocurrent detectors 18a, 18b, and 18c made of lead glass so as to go around a, 12b, and 12c are attached to the epoxy resin 1
4 Embedded inside and set up. Optical fiber 2 for transmitting and receiving light
1 is a polarizer 19a, 19b, 19c and an analyzer 20a, 2
0b, 20c through photocurrent detectors 18a, 18b, 1
8c is connected. The Faraday effect will not be discussed here.

Besides, a photocurrent detector utilizing the Faraday effect of an optical fiber can be applied.

[0028]

As described above, in the gas-insulated switchgear of the present invention, it is possible to accurately determine the accident zone and provide information for early recovery of a GIS accident.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of the configuration of a gas-insulated switchgear of the present invention.

2A and 2B are views showing an embodiment of a current detector according to an embodiment of the present invention, FIG. 2A is a view seen from an axial direction, and FIG. 2B is a sectional view taken along line AA.

FIG. 3 is a diagram showing an example of a configuration of a gas insulated switchgear.

FIG. 4 is a diagram showing an example of a conventional gas-insulated switchgear relating to the present invention.

[Explanation of symbols]

 1 Insulation Spacer 2 Current Signal Transmission Section 3 Gas Insulated Switchgear (GIS) 4 Accident Zone Judgment Section 7 Signal Processing Circuit

Claims (4)

[Claims] 1. A gas-insulated switchgear in which a container accommodating each element is divided into a plurality of gas compartments, and a current detector for detecting a current of each of three-phase buses built in an insulating spacer partitioning each gas compartment. A gas-insulated switchgear provided with: an accident zone determination unit that determines the gas zone in which an accident has occurred by comparing the magnitude of the current flowing through each insulating spacer with a predetermined determination level. 2. The gas-insulated switchgear according to claim 1, wherein the gas division in which the accident has occurred is determined as a predetermined determination level of the accident division determination unit from the current flowing through another insulating spacer. 3. An accident segment judging section obtains a vector sum of three-phase currents in each insulating spacer and calculates a zero-phase current, and the magnitude thereof or the magnitude of its temporal change is set as a predetermined decision level. The gas-insulated switchgear according to claim 1 or 2, wherein a gas section in which an accident has occurred is determined by comparison. 4. The gas-insulated switchgear according to claim 1, 2 or 3, wherein the current detector comprises a photocurrent detector.